Over the past ninety-odd years i.e. ever since the establishment of the first government funded agricultural college, the Department of Agriculture, under its different titles, played an indispensable role in support of agricultural research at tertiary institutions. However, its direct involvement with university faculties was terminated in 1973 when the faculties were fully incorporated into the universities. Undoubtedly the Department has a vital interest in the well-being of tertiary institutions for the training of high level manpower needed to fulfil its research mandate. At present its indirect and direct support of research at university faculties is in the form of researchers seconded and funded for post-graduate studies, the initiation and funding of research contracts by university personnel and the recent expansion of its facility for research fellowships aimed at closer cooperation with and support for tertiary institutions.
{"title":"Role and responsibility of the Department of Agriculture and Water Supply in and for agricultural research at tertiary education institutions","authors":"F. D. Merwe","doi":"10.4102/SATNT.V8I2.874","DOIUrl":"https://doi.org/10.4102/SATNT.V8I2.874","url":null,"abstract":"Over the past ninety-odd years i.e. ever since the establishment of the first government funded agricultural college, the Department of Agriculture, under its different titles, played an indispensable role in support of agricultural research at tertiary institutions. However, its direct involvement with university faculties was terminated in 1973 when the faculties were fully incorporated into the universities. Undoubtedly the Department has a vital interest in the well-being of tertiary institutions for the training of high level manpower needed to fulfil its research mandate. At present its indirect and direct support of research at university faculties is in the form of researchers seconded and funded for post-graduate studies, the initiation and funding of research contracts by university personnel and the recent expansion of its facility for research fellowships aimed at closer cooperation with and support for tertiary institutions.","PeriodicalId":30428,"journal":{"name":"South African Journal of Science and Technology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1989-03-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70517930","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Under various circumstances and in different species the outward expression of learning varies considerably, and this has led to the classification of different categories of learning. Just as there is no generally agreed on definition of learning, there is no one system of classification. Types of learning commonly recognized are: Habituation, sensitization, classical conditioning, operant conditioning, trial and error, taste aversion, latent learning, cultural learning, imprinting, insight learning, learning-set learning and instinct. The term memory must include at least two separate processes. It must involve, on the one hand, that of learning something and on the other, at some later date, recalling that thing. What lies between the learning and (he remembering must be some permanent record — a memory trace — within the brain. Memory exists in at least two forms: memory for very recent events (short-term) which is relatively labile and easily disruptable; and long-term memory, which is much more stable. Not everything that gets into short-term memory becomes fixed in the long-term store; a filtering mechanism selects things that might be important and discards the rest.
{"title":"Learning and memory","authors":"P. Ryke","doi":"10.4102/SATNT.V8I1.863","DOIUrl":"https://doi.org/10.4102/SATNT.V8I1.863","url":null,"abstract":"Under various circumstances and in different species the outward expression of learning varies considerably, and this has led to the classification of different categories of learning. Just as there is no generally agreed on definition of learning, there is no one system of classification. Types of learning commonly recognized are: Habituation, sensitization, classical conditioning, operant conditioning, trial and error, taste aversion, latent learning, cultural learning, imprinting, insight learning, learning-set learning and instinct. The term memory must include at least two separate processes. It must involve, on the one hand, that of learning something and on the other, at some later date, recalling that thing. What lies between the learning and (he remembering must be some permanent record — a memory trace — within the brain. Memory exists in at least two forms: memory for very recent events (short-term) which is relatively labile and easily disruptable; and long-term memory, which is much more stable. Not everything that gets into short-term memory becomes fixed in the long-term store; a filtering mechanism selects things that might be important and discards the rest.","PeriodicalId":30428,"journal":{"name":"South African Journal of Science and Technology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1989-03-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70517884","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Bepaling van mannekragaanwending en opleidingsbehoeftes t.o.v. narkosetoediening in die Oranje-Vrystaat","authors":"E. D. Wet","doi":"10.4102/SATNT.V7I3.919","DOIUrl":"https://doi.org/10.4102/SATNT.V7I3.919","url":null,"abstract":"","PeriodicalId":30428,"journal":{"name":"South African Journal of Science and Technology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1988-03-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70517830","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The use of non-linear capacitors improves the efficiency of turn-off snubbers for power electronic switches. The parameters for the determination of non-linear ferro-electric capacitors are discussed and a novel measuring method for the determination of the maximum operating voltage is suggested. The procedure to select ferro-electric capacitors is also discussed.
{"title":"Determination of the operating voltage for non-linear capacitors as turn-off snubbers in power electronic switches","authors":"A. Lutsch, J. Schoeman, J. D. Wyk","doi":"10.4102/SATNT.V7I3.916","DOIUrl":"https://doi.org/10.4102/SATNT.V7I3.916","url":null,"abstract":"The use of non-linear capacitors improves the efficiency of turn-off snubbers for power electronic switches. The parameters for the determination of non-linear ferro-electric capacitors are discussed and a novel measuring method for the determination of the maximum operating voltage is suggested. The procedure to select ferro-electric capacitors is also discussed.","PeriodicalId":30428,"journal":{"name":"South African Journal of Science and Technology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1988-03-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70517765","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Die komitee wat in samewerking met die Vakterminologiediens van die Departement van Nasionale Opvoeding ’n Engels-Afrikaanse Woordeboek vir meganiese ingenieurs saamstel, kom periodiek voor probleme te staan, soos byvoorbeeld twyfel of vir sekere terme ’n taalkundig en wetenskaplik korrekte vertaling ook algemeen aanvaarbaar is, want die “ vloertaal” is nou maar dinamies en nie altyd logics nie. Verder is daar ook gevalle waar een Engelse term vir verskeie begrippe gebruik word waarvoor in Afri kaans afsonderlike terme bestaan. Die volgende voorbeelde word genoem: “ krities” of “ kritiek” ; “ altitude” of “ hoogte bo seespieel” ; persoonsname in vakterme; “ girder” vertaal as “ leer” .
{"title":"Woordeboek vir meganiese ingenieurs","authors":"H. G. Denkhaus","doi":"10.4102/satnt.v6i2.949","DOIUrl":"https://doi.org/10.4102/satnt.v6i2.949","url":null,"abstract":"Die komitee wat in samewerking met die Vakterminologiediens van die Departement van Nasionale Opvoeding ’n Engels-Afrikaanse Woordeboek vir meganiese ingenieurs saamstel, kom periodiek voor probleme te staan, soos byvoorbeeld twyfel of vir sekere terme ’n taalkundig en wetenskaplik korrekte vertaling ook algemeen aanvaarbaar is, want die “ vloertaal” is nou maar dinamies en nie altyd logics nie. Verder is daar ook gevalle waar een Engelse term vir verskeie begrippe gebruik word waarvoor in Afri kaans afsonderlike terme bestaan. Die volgende voorbeelde word genoem: “ krities” of “ kritiek” ; “ altitude” of “ hoogte bo seespieel” ; persoonsname in vakterme; “ girder” vertaal as “ leer” .","PeriodicalId":30428,"journal":{"name":"South African Journal of Science and Technology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1987-03-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70517668","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Fungal contamination of agricultural products can prove to be harmful to humans and domestic animals as these fungi produce a variety of mycotoxins which can eventually occur in food. Acute intoxications with mycotoxins occur regularly in farm animals but, fortunately, are infrequently observed in humans. However, the chronic exposure of humans to mycotoxins occurs regularly. Such exposures are potentially teratogenic and carcmogenic and can suppress the immune system. It is presently impossible to establish safe levels of exposure for most mycotoxins due to scanty epidemiological data and insufficient observations on experimental animals. With respect to aflatoxin all available data point to a real health risk. Risk analysis based on epidemiological observations shows that the liver-cancer risk for individuals in South Africa is potentially increased by continued exposure to the present legally permitted level of aflatoxin in food.
{"title":"Mycotoxins and health risks","authors":"P. G. Thiel","doi":"10.4102/SATNT.V5I3.991","DOIUrl":"https://doi.org/10.4102/SATNT.V5I3.991","url":null,"abstract":"Fungal contamination of agricultural products can prove to be harmful to humans and domestic animals as these fungi produce a variety of mycotoxins which can eventually occur in food. Acute intoxications with mycotoxins occur regularly in farm animals but, fortunately, are infrequently observed in humans. However, the chronic exposure of humans to mycotoxins occurs regularly. Such exposures are potentially teratogenic and carcmogenic and can suppress the immune system. It is presently impossible to establish safe levels of exposure for most mycotoxins due to scanty epidemiological data and insufficient observations on experimental animals. With respect to aflatoxin all available data point to a real health risk. Risk analysis based on epidemiological observations shows that the liver-cancer risk for individuals in South Africa is potentially increased by continued exposure to the present legally permitted level of aflatoxin in food.","PeriodicalId":30428,"journal":{"name":"South African Journal of Science and Technology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1986-03-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70518108","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Terminologie vir Drywingselektronika (Deel IV) Tiristorterminologie (vervolg)","authors":"C. G. Steyn, J. D. V. Wyk","doi":"10.4102/SATNT.V5I1.968","DOIUrl":"https://doi.org/10.4102/SATNT.V5I1.968","url":null,"abstract":"","PeriodicalId":30428,"journal":{"name":"South African Journal of Science and Technology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1986-03-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70517987","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"n Festschrift gewy aan professor H.W. Snyman","authors":"O. W. Prozesky","doi":"10.4102/satnt.v4i2.1026","DOIUrl":"https://doi.org/10.4102/satnt.v4i2.1026","url":null,"abstract":"","PeriodicalId":30428,"journal":{"name":"South African Journal of Science and Technology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1985-03-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70517677","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Meegaande terminologie is ’n vervolg op die reeds gepubliseerde deel I en II van die terminologie vir Drywingselektronika.'’ Slegs die meer algemene terme vir tiristors word hier behandel. In toekomstige bydraes sal aandag geskenk word aan die beskrywing, klassifikasie en simboliese voorstelling van tiristors. Daar is sover moontlik gepoog om die voorskrifte van die Internasionale Elektrotegniese Kommissie^’"'’ na te volg. Lesers se kommentaar op enige aspek van die drywingselektronikaterminologie sal verwelkom word. Die benaming tiristor word hier gebruik vir ’n simmetriese tiristor (sperrende triodetiristor).
{"title":"Terminologie vir Drywingselektronika (Deel III) Tiristorterminologie","authors":"C. G. Steyn, J. D. V. Wyk","doi":"10.4102/satnt.v4i4.1047","DOIUrl":"https://doi.org/10.4102/satnt.v4i4.1047","url":null,"abstract":"Meegaande terminologie is ’n vervolg op die reeds gepubliseerde deel I en II van die terminologie vir Drywingselektronika.'’ Slegs die meer algemene terme vir tiristors word hier behandel. In toekomstige bydraes sal aandag geskenk word aan die beskrywing, klassifikasie en simboliese voorstelling van tiristors. Daar is sover moontlik gepoog om die voorskrifte van die Internasionale Elektrotegniese Kommissie^’\"'’ na te volg. Lesers se kommentaar op enige aspek van die drywingselektronikaterminologie sal verwelkom word. Die benaming tiristor word hier gebruik vir ’n simmetriese tiristor (sperrende triodetiristor).","PeriodicalId":30428,"journal":{"name":"South African Journal of Science and Technology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1985-03-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70517756","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
’n Betroubare maar stadig werkende respirometer is vergelyk met ’n nuut ontwerpte Clark-elektroderespirometer. As metingsmateriaal is van Labeo capensis, ’n varswatervis, gebruik gemaak. Die resultate is statisties ontleed. Daar is gevind dat die iesings van die Clark-elektroderespirometer effens hoer is as die van die klassieke manometriese respirometer van Scholander.
{"title":"A respirometer for aquatic animals standardized against the Scholander respirometer","authors":"W. V. Aardt, H. S. Steyn","doi":"10.4102/SATNT.V3I4.1091","DOIUrl":"https://doi.org/10.4102/SATNT.V3I4.1091","url":null,"abstract":"’n Betroubare maar stadig werkende respirometer is vergelyk met ’n nuut ontwerpte Clark-elektroderespirometer. As metingsmateriaal is van Labeo capensis, ’n varswatervis, gebruik gemaak. Die resultate is statisties ontleed. Daar is gevind dat die iesings van die Clark-elektroderespirometer effens hoer is as die van die klassieke manometriese respirometer van Scholander.","PeriodicalId":30428,"journal":{"name":"South African Journal of Science and Technology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1984-03-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70517617","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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